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Activation Of Extracellular-Signal Regulated Kinase (Erk1/2) By Fluid Shear Is Ca2+- And Atp-Dependent In Mc3t3-E1 Osteoblasts, Dawei Liu, Damian C. Genetos, Ying Shao, Derik J. Geist, Jiliang Li, Hua Zhe Ke, Charles H. Turner, Randall L. Duncan

School of Dentistry Faculty Research and Publications

To determine the role of Ca²⁺ signaling in activation of the Mitogen-Activated Protein Kinase (MAPK) pathway, we subjected MC3T3-E1 pre-osteoblastic cells to inhibitors of Ca²⁺ signaling during application of fluid shear stress (FSS). FSS only activated ERK1/2, rapidly inducing phosphorylation within 5 min of the onset of shear. Phosphorylation of ERK1/2 (pERK1/2) was significantly reduced when Ca_i²⁺ was chelated with BAPTA or when Ca²⁺ was removed from the flow media. Inhibition of both the L-type voltage-sensitive Ca²⁺ channel and the mechanosensitive cation-selective channel blocked FSS-induced pERK1/2. Inhibition of phospholipase C with U73122 significantly reduced …